from functools import lru_cache


@lru_cache()
def block_combinations(row_length: int):
    block_sizes = [2, 3, 4]
    if row_length < 0:
        return 0

    if row_length == 0:
        return 1

    # space
    result = block_combinations(row_length - 1)

    # one of the blocks
    for block_length in block_sizes:
        result += block_combinations(row_length - block_length)

    return result


def euler_117():
    return block_combinations(50)


if __name__ == "__main__":
    solution = euler_117()
    print("e117.py: " + str(solution))
    assert(solution == 100808458960497)